IF you submitted the design for Rob Harley to the Patent Office it would be rejected on the long-established principle that they do not accept claims for perpetual motion machines.

The Glasgow Warriors flanker put in an immense shift in his side's 15-13 European Champions Cup victory over Montpellier on Saturday, tackling any member of the French side who even thought about approaching the gain line and generally making a nuisance of himself from start to finish. But then, immense shifts have become the trademark of the player who, uniquely, was involved in every one of the Warriors' PRO12 games last season.

Yet as staggering as that achievement was, it also reflected the fact that Harley had slipped down the international pecking order and was deemed surplus to Scotland's requirements during last year's autumn Test programme and the RBS 6 Nations campaign which followed. Indeed, his only involvement on Scotland's 2013 trip to South Africa was as a replacement against Italy, and he had almost exactly a full year to wait before he represented his country again, against Argentina on this year's summer tour.

In the intervening period, the Scotland blindside role was occupied at different times by Al Strokosch, Johnnie Beattie and Ryan Wilson, while Kieran Low (usually on the bench) and Kelly Brown (usually on the opposite flank) were also around to fill the slot if needed. However, with Wilson injured and Brown not chosen for this year's November squad, the door is open for Harley to return to the team.

The 24-year-old did his case no harm in Glasgow's epic defensive display against Montpellier. He claims that he does not know his tackle count in that game, but if he was paid by the hit he could probably have retired on Sunday morning. But then, there are lies, damned lies and tackle statistics, and Harley reckons he was cheated out of one.

"What was a little bit frustrating is the way they record tackles as either dominant, efficient, passive or an offload miss," he explained. "There was one where I chased the kick, hit the guy hard and was going to put him into touch, until he threw it over his head. Technically that's an offload miss, so I'm not going to get a good mark for that."

Harley can take comfort from the fact that Scotland coach Vern Cotter seems the sort of fellow who would rather trust his instincts than be a slave to a stack of numbers.

Cotter also likes what he has seen of Harley as a human being and volunteered the suggestion that he could even be in the frame to lead the side into the November Test against Argentina now that Grant Gilchrist has been ruled out with a broken arm. "I think Rob Harley is an interesting character," said Cotter at Scotland's Newcastle training base. "He is a leader and very professional in what he does."

In truth, it would be a left-field choice, as Harley has always seemed a more natural spear carrier than leading man. But, as he also comes over as a more confident and self-assured individual now than he was when he first broke into the Glasgow side four years ago, maybe the coach is onto something.

Maybe he is the kind of player who would be more formidable still with that burden of responsibility on his shoulders.

Certainly, he is no shrinking violet as far as his predictions for November are concerned. Harley was one of 17 Glasgow players originally chosen for the November squad, a number which has since increased with the addition of Peter Horne, and he feels the momentum the Warriors have created over the past few weeks can be carried over into the international arena.

"There is a notable confidence from the way we have played [for Glasgow]," said Harley, when asked about the prospect of victories against Argentina, New Zealand and Tonga. "We have the ability to go out and win those games. It feels the same in the Scotland camp, that we feel we can win all three Tests."

While Harley was an ever-present for Glasgow in the bread-and-butter of league competition last season, he had the good fortune to miss out on their Heineken Cup meeting with Toulon, when the reigning European champions ripped the Scots to shreds in the first half.

It was a brutal experience for Gregor Townsend's side, but salutary too. They have since put the lessons learned that day to good use.

"Before the game [last weekend] we were talking about not just waiting to see what Montpellier had," said Harley. "Against Toulon, we'd played great rugby in the second half, but they blew us away in the first half and got too far ahead while we were sitting back.

"We realised that, if we play as we can, we can compete with any team. So we went out there hard and set our mark on the game, knowing we could win those games. That's what we showed against Montpellier.

"It's a lesson we want to take with us for Scotland. We will have that confidence regardless of how the game goes. We can frustrate anyone."

That mixture of stroppiness and self-belief is the sort of thing to which Cotter warms in a player. When he was in charge of Clermont Auvergne, Cotter dynamited the club's culture of being the perennial bridesmaids of French rugby and eventually led them to the national championship title that had eluded them for so long.

If he wants to do something similar with Scotland, Harley could yet emerge as his right-hand man.